The present invention is directed to an expansion dowel assembly to be anchored in a borehole in a receiving material and is made up of a dowel body and one or a number of wedge-shaped expansion members. Means for applying a load are located at the trailing end of the dowel body relative to the direction in which it is inserted into a borehole. Wedge-shaped recesses are formed in the circumferential surface of the dowel body adjacent its leading end for receiving the expansion members. The bases of the recesses are inclined inwardly from the leading end of the dowel body toward the axis thereof. Each of the one or more expansion members is connected by a web to the dowel body and the web is severed or broken when the dowel assembly is inserted into the borehole.
In a known expansion dowel, the dowel body is rod-shaped and includes a wedge-shaped expansion member. The wedge-shaped expansion member is positioned within a wedge-shaped recess in the dowel body and is connected with the dowel body by a severable web located at the base of the recess. In a space between the base of the recess and the expansion member, a severing member is positioned in the form of a trapezoidally-shaped plate and extends outwardly beyond the circumferential contour of the dowel body. To install this known expansion dowel, it is driven into a borehole and the severing member, because it extends beyond the circumferential surface of the dowel body and abuts against the surface of the borehole, moves against the web and severs it. When the expansion dowel has reached a sufficient depth in the borehole, the dowel body is pulled opposite to the insertion direction by applying a load and the wedge-shaped expansion member anchors the dowel body in the borehole.
The need for a severing member for cutting the web has proved to be disadvantageous in such an expansion dowel, since in addition to the effort required to place the dowel there is the problem of correct and secure positioning of the severing member. Moreover, the severing member, projecting outwardly from the dowel body,considerably increases the resistance of he expansion dowel to being inserted into a borehole.